Well, I don't see how the horses could be any greater contributor to the flies than any other livestock including chickens, but the fly predators from Arbico are fantastic helpers. Only problem with chickens, I suppose they would eat the fly predators as well as the flies if they can reach them.
You have to fight flies on many fronts. Diotamaceous earth helps greatly. Purple Martin houses and the purple martins they attract are fantastic for flies and mosquitoes, as long as their season lasts in your area.
The fly strips and fly baited bottles that hang away from the chicken's reach are another weapon of war.
Things that refract light also scare flies and mosquitos away. But they may scare the chickens too. IE, clear plastic bags filled with water hung every 8 feet or so around the area you are trying to keep the flies away from. Also, the very shiny silver CD or DVD discs you get through the mail, hung to swing, sway and refract light do the same.
Connie
